The present invention relates to a color correction device that performs color correction when image information of a document image read by a color image forming apparatus is outputted to a printer, or image information in a facsimile is outputted to a printer, and more particularly relates to a color correction device having a color conversion function.
Recently, color reproducibility of very high accuracy is required for full color images. Accordingly, a color correction method of simple linear masking is not sufficient. Therefore, more accurate methods have been proposed, including a 2 stage masking method, a nonlinear masking method, an LUT (look-up-table) system, and a method solving a Neugebauer Equation.
However, these highly accurate methods are disadvantageous in that: the hardware becomes complicated; and further the adjusting operation is not simple. For example, when it is required to change the shade of a color and one coefficient is carelessly changed, colors that are not required to be changed are also influenced, and further gray balance is affected. In order to solve the aforesaid problems, it is necessary to find a correction coefficient through a complicated calculation. As described above, there are many problems from the viewpoint of operability.
A color conversion method by which a specific color on a document is converted into another color, is utilized in the field of designing. However, after color conversion has been completed, a color boundary appears on a periphery of the color-converted portion. Therefore, partial correction such as retouching is required. In the case of a color component conversion system, it is not necessary to perform partial correction. In the aforementioned case, however, the range of color conversion becomes wide, so that even colors not to be converted are influenced, and the gray balance is lost. Furthermore, in order to provide a color correction device with color conversion function, it is necessary to install hardware for color conversion that is provided separately from the color correction device. Consequently, the cost is raised.